This is of a dry vacuum pump is a pump that will not use any fluids to make a vacuum or contact the process gas and may also discharge to atmosphere. … Timing gears with oil reservoirs and close clearances between your rotors and casing are extra attributes that define a dried out vacuum pump.
Principle of Operation
Dry screw vacuum pumps operate with two screw rotors rotating in opposite directions. This traps the medium to be pumped between your cylinder and the screw chambers and transports it to the gas discharge. … It also results in a lesser temperature load of the compressed gas.